The National Institute of Water and Atmospheric Research has released its new summer forecast and while it doesn't believe there will be another severe drought, it says farmers in some parts of the country need to be careful.
Principal scientist Brett Mullins said farmers in Canterbury and Otago need to keep their eye on the sky.
As of early December the driest parts of the country are Northland, Waikato and parts of Bay of Plenty.
But Mr Mullins said normal or above normal rainfall is expected over the summer period as a whole and if the forecast is as anticipated there are not likely to be problems.
He said in Canterbury and North Otago normal or below normal soil moisture is expected so it could develop problems as the season progresses.
Otago Regional Council has issued an irrigation restriction warning to farmers saying they need to begin conserving water.
The council says many rivers in the region are so low they're at levels not normally seen until late summer.
Unless there's substantial rainfall - rationing may begin later this month or early next year.